When I teach states of matter to elementary school kids we investigate the 3 main categories: Solid, Liquid, and Gas. A gas takes up the space/area that it is given. A liquid takes the shape of the container it is in. A solid does not change it’s shape. Well, there is a new (2006) technology called self-healing materials. Here is a link to a short clip about self-healing cement:

http://www.cnn.com/2015/05/14/tech/bioconcrete-delft-jonkers/

This is amazing to me. Having cement, cloth, painted walls able to “fix” themselves before it becomes a problem has so many real applications. This is one way my thinking has changed. Even if it’s solid cement, it can change it’s shape. How cool is that?